Adhesives and Sealants Play Crucial Role in Hydrogen-Based Fuel Cell Assembly
As demand for hydrogen-based fuel cells increases, sealants and adhesives play a crucial role in automated production. Hydrogen-based fuel cells achieve high performance and are energy-efficient. They produce no harmful emissions because only water and electrical energy are released when hydrogen reacts with oxygen. The technology holds considerable potential for powering electric vehicles as the world transitions away from fossil-based fuels.
Since hydrogen is the smallest of all molecules, the adhesives and sealants used for fuel cells must ensure a very tight seal in order to prevent diffusion. Silicones and polyurethanes are developed for this purpose. Additionally, these products’ low gas permeability has been confirmed by ZBT, the hydrogen and fuel cell center in Duisburg, Germany. The products can be used both for fuel cells themselves (“stacks”) and in the surrounding system (“balance of plant”).
Fuel cells consist of several functional layers that can differ both in terms of the materials and components used as well as in terms of the working principle. One of the most common types, which is currently being widely researched because of its suitability for the automotive sector, is the so-called PEM fuel cell (Proton Exchange Membrane Fuel Cell).
The bipolar plates ensure a steady supply of hydrogen to the cells and simultaneously control the release of electrical energy. Since hydrogen is flammable and can form explosive mixtures (oxyhydrogen) in oxygen-containing atmosphere, reliable sealing of the individual cells is essential. The sealing materials must not only be highly impermeable to gas; they must also be resistant to challenging conditions such as continuous high temperatures of up to 120 °C or low pH. Furthermore, if the bipolar plates have tolerances due to manufacturing, this results in uneven pressure distribution on the sealing materials, which has to be compensated – especially while the stacks are being pressed.
Source: Adhesives Magazine/WEVO-CHEMIE GmbH